PL/SQL: optional arguments for procedures/funcs

Hi PL/SQL gurus !

Can it be determined if optional argument is set by a call or default value is used ?

Setting it to some default value (e.g. null) is NOT ENOUGH because I need to find out is that null forced by explicit call with that (e.g.null) value,
or the argument was not set because parameter in function call was ommited so default value is used.

In short, i need a function like this: IsParameterPresent( parameter_name )

please help,

Vedran

• using this procedure it is not possible to set name to null, even if explicitly called to do so: update_name( null );
• update_name() should set name to some default value ('john smith'). procedure update_name( cName varchar2 default null) cNewName varchar2( 2000 ); begin if cName is null then -- is it called by update_name( null ) or update_name() (no parameters) ? cNewName := 'john smith'; else cNewName := cName; end if; update person set name = cName; end;